DECAY OF MASS-SEPARATED HG-189M (8.7 MIN) AND HG-189G (7.7 MIN) TO AU-189

The decays of Hg-189 (8.7 min; J(pi) = 13/2(+)) and Hg-189 (7.7 min; J (pi) = 3/2(-)) have been studied with mass-separated sources from the UNISOR facility. Multiscaled spectra of gamma-rays, X-rays, and conver sion electrons, as well as gamma gamma t, gamma Xt, e gamma t, and eXt coincidences were obtained, Decay schemes have been constructed incor porating > 95% of the decay intensities assigned to the high-spin and low-spin decays, The gamma-ray gated conversion-electron spectra permi tted the determination of 119 conversion-electron subshell ratios, Por tions of the level scheme bear a remarkable resemblance to the heavier and lighter odd-mass Au isotopes. An extensive band of states is obse rved built upon the h(9/2), intruder state at 325 keV. This band is ma rkedly different from the corresponding bands in Au-187 and Au-185, in dicating a major change in the cores, i.e. between Pt-188 and Pt-186,P t-184. Evidence for oblate-hole-prolate-particle symmetry in Au-189 is discussed. Completeness of complex decay schemes far from stability i s addressed.